Solar wind spilling down from this northern coronal hole is brushing against Earth's magnetic field today. Credit: SDO/AIA

Noctilucent CloudsOur connection with NASA's AIM spacecraft has been restored! New images from AIM show that the southern season for noctilucent clouds (NLCs) is underway. Come back to this spot every day to see AIM's "daily daisy," which reveals the dance of electric-blue NLCs around the Antarctic Circle..

SOLAR WIND STREAM GRAZES EARTH: Solar wind spilling from a northern hole in the sun's atmosphere is grazing Earth's magnetic field today. The indirect pressure of the gaseous material sparking intermittent auroras around the Arctic Circle, while stopping short of full-fledged geomagnetic storms. Free:Aurora Alerts

SOLAR FLARE! The unstable magnetic canopy of sunspot AR2699 erupted on Feb. 7th (1347 UT), producing a C8-class solar flare. A pulse of extreme UV radiation from the flare ionized the top of Earth's atmosphere, browning out shortwave radio transmissions below ~10 MHz over the South Atlantic ocean: map.

This class of explosion would be considered minor during more active phases of the solar cycle, but now on the eve of Solar Minimum it is a significant eruption. AR2699 is becoming larger and more unsettled as it turns toward Earth, so more flares are possible in the hours and days ahead.

TESLA ROADSTER LEAVES EARTH: Elon Musk's cherry red Roadster has left Earth orbit. Just after sunset on Feb. 6th, sky watchers across the southwestern USA saw a flash of light and a cloud of rocket exhaust signaling the electric car's escape from the gravity well of our planet. "The Falcon Heavy's third stage burn was clearly visible from Trinidad, Colorado, around 7:30 pm MST," reports Zachariah Borrego. "While I was watching, my girlfriend Tamera Morton took this incredible picture of the expanding cloud."

The event was widely seen from southern California to New Mexico and Colorado. Experienced observers likened the luminous tip of the cloud, where the Tesla Roadster was located, to a 1st magnitude star. An all-sky camera at the University of Arizona's MMT Observatory recorded a fish-eye video of the booster burning across the sky over Mount Hopkins: watch it.

UNIQUE VALENTINE'S GIFT: Nothing says "I Love You" like a Valentine's pendant from the edge of space. On Dec. 31, 2017, the students of Earth to Sky Calculus flew a payload-full of these heart-shaped pendants to the stratosphere, 35.1 km (115,158 feet) above Earth's surface:

You can have one for $119.95. Each glittering pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the edge of space. Sales of this pendant support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.

SOLAR RADIO BURST: Sunspot AR2699 is making some noise--literally. "Yesterday, I heard a surge of static coming from the loudspeaker of my shortwave radio telescope in New Mexico," reports amateur astronomer Thomas Ashcraft. "The source was sunspot AR2699." Turn up the volume and click to play:

These radio sounds are caused by beams of electrons--in this case, accelerated by B-class explosions in the sunspot's magnetic canopy. As the electrons slice through the sun's atmosphere, they generate a ripple of plasma waves and radio emissions detectable on Earth 93 million miles away. Astronomers classify solar radio bursts into five types; Ashcraft's recording captured a Type III.

"This may be one the last solar radio bursts of the present solar cycle as we head into deep solar minimum," says Ashcraft. "I am hoping for more activity to appear on the spectrograph today." Free:Solar Flare Alerts

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

On Feb. 7, 2018, the network reported 12 fireballs.(12 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.

Cosmic Rays in the Atmosphere

Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We've been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:

This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.

What is this all about? Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 13% since 2015:

Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation.

The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.